Because of a growing demand for petrochemicals, including olefins and aromatics, there is interest in the conversion of alternative feedstocks into useful petrochemicals. One alternative feedstock is coker naphtha, which can be a hydrocarbon stream produced by the thermal cracking of long chain hydrocarbons in a coker unit. During oil refinery processing, the coker unit converts residual oil from a distillation column into shorter chain hydrocarbons, including low molecular weight hydrocarbon gases and naphtha. Coker naphtha can contain unsaturated hydrocarbons such as olefins, diolefins and aromatics, as well as sulfur, silica, and nitrogen. Diolefins, sulfur, and silica in the coker naphtha stream can cause reactor fouling and complicate the production of high value olefins and aromatics.
Certain methods for generating potentially higher value petrochemicals from a hydrocarbon stream are known in the art. For example, European Patent Publication No. EP2644584 discloses methods of producing aromatics and olefins from a refinery fraction containing aromatics, including a hydrogen-processing reaction step, a catalytic cracking step, a separation step, and a transalkylation step, and optionally a recirculation step. Chinese Patent Publication No. CN102795958 discloses techniques for generating aromatics and ethylene from naphtha, by the reforming of naphtha to produce aromatics and alkanes and the steam cracking of produced alkanes. U.S. Pat. No. 4,179,474 discloses a method of pyrolyzing naphtha to produce ethylene, including blending a catalytically hydrogenated naphtha stream with a sulfur containing compound. U.S. Pat. No. 4,138,325 discloses a process for the conversion of gas oil to a naphtha pyrolysis feedstock and needle coke, including thermally cracking gas oil to produce cracked naphtha and aromatic tar oil.
U.S. Pat. No. 6,153,089 discloses methods of converting an olefinic hydrocarbon stream to light olefins and aromatics using a dehydrogenated metal catalyst. U.S. Patent Publication No. 2003/0181325 discloses a catalyst including an acid component and at least one metal component for converting paraffins to light olefins. European Patent Publication No. EP1734098 discloses a process for generating olefins and aromatics by the catalytic cracking of naphtha. U.S. Pat. No. 3,556,987 discloses producing acetylene, ethylene, and aromatics from crude oil by distilling crude oil to form multiple streams, including coker naphtha, heavy naphtha, and light naphtha. Coker naphtha and heavy naphtha are combined and reformed to produce a reformed product, including aromatics, and a raffinate, which is fed to a hydrocarbon pyrolysis furnace with the light naphtha to produce ethylene.
However, there remains a need for techniques of producing olefins and aromatics from a coker naphtha stream.